The Clinical Core provides the Projects with data from epidemiological, neuropsychological, medical and physical measures. The Core is responsible for obtaining informed consent for participation in the EAS and for participation in the brain donation program. The Core's primary function is characterization of EAS subjects through baseline and annual follow-up clinical and neuropsychological evaluations, including the assignment of cognitive and dementia diagnoses. All subjects undergo an in-person Clinical Core evaluation at baseline and subsequent 12-month intervals. The Core also conducts Consensus Case Conferences to assign clinical cognitive outcomes for each subject at each Wave (annual evaluation). Clinical outcomes assigned include: 1) Diagnosis of DSM-IV 'Dementia'versus 'No Dementia';2) for subjects with dementia, subtypes are diagnoses using standard criteria;and 3) Intermediate States of Cognitive Impairment (amnestic Mild Cognitive Impairment, non-amnestic Mild Cognitive Impairment). The Clinical Core cooperates with the Administrative Core to collect follow-up medical and neuropsychological information for study subjects no longer able to return for in-person evaluations. Data from the Clinical Core are used to determine subject eligibility for participation in Projects. Finally, the Clinical Core collects, distributes, and banks biological specimens for current and future assays. RELEVANCE (See instructions): The Clinical Core collects epidemiological, neuropsychological and neurological data to service research projects. These data are used to assign diagnoses, to develop other outcome variables, correlate with neuropathologic findings and experimental neuropsychological procedures and locomotor outcomes. The Clinical Core ascertains all the confounders and effect modifiers of dementia risk.